问题补充:
Food supplies in the flood-stricken area . We must act immediately before there’s none left.
A. have run out
B. are running out
C. have been run out
D. are being run out
答案:
A. have run out
(答案→)B. are running out
C. have been run out
D. are being run out
解析:句意,在发生洪水的灾区食品供应即将用完。我们必须在全部用完之前采取行动。runout为不及物动词短语,不能使用被动形式,由此可排除C和D两个选项。A选项为现在完成时,原题中想要表达将要用完,还没有用完,所以不合题意,B选项为现在进行时态,可以表示将来,符合题意,故选B。